Counterbalancing system for engines



Nov. 27, 1928.

R. WINTZER COUNTERBALANCING SYSTEM FOR ENGINES Filed April 22, 1927 Patented Nov. 27, 1928. V H

UNITED STATES PATENT OFFICE.

RUDOLPH WINTZER, OF MILWAUKEE, WISCONSIN, ASSIGHOR TO NORD'BERG MANU- FACTURING COMPANY, OF IVIILVTAUKEE, Vi/ISCONSIN, A CORPORATION OF WIS- CONSIN.

COUNTERBALANCING SYSTEM FOR ENGINES.

Application filed April 22, 1927. Serial No. 185,832.

This invention relates to reciprocating ena revolving mass to the extent of of its gines and particularly-toaniode of balancing total mass and a reciprocating mass to the a four cylinder engine having an unusual extentof of its total mass. 55 crank arrangement peculiarly adapted to Generally stated, balancing is effected as 5 certain fields of service. fOHOWSI The crank shaft is so designed that In reversing rolling mills it is the practice the two crank throws at 45 with each other to use engines devoid of fly wheels to permit are placed symmetrically with reference to quick reversal, and it is important to have an the long1tudinal center line of the engine and 60 engine which will run smoothly at low speed preferably are the two end cranks. Each and be capable of starting under full load. such crank carries a counterweight (which In recent years successful efforts have been may be formed in two similar parts at oppoi'nade to control such engines in starting, site sides of the crank pin). The counterstopping and reversal solely by varying the weights for the two cranks are identical and 65 cut-oh. At the same time the steam economy 1 their centers of mass lie in a common plane,

has been greatly improved by using short which is the plane passing through the axis cut-offs and a maximum cut-ofi at about of the crank shaft and bisecting the 45 stroke. To secure smooth torque and good crank interval. Thus each counterweight is starting power it is necessary to use a reladisplaced 22%" from a position directly 0pively large number of cylinders, say four posite its crank.

double-acting cylinders, and to arrange such Each counterweight somewhat overbalcylinders so that the individual working ances the related revolving mass, i. e., one spaces deliver their impulses seriatim at uni- 45 crank mass plus the mass of its conf crank intervalg necting rod. The amount of such overbal- In a four cylinder engine the desired sucancing is a function of the relation of the ro- 25 cession of impulses is best secured by the tating masses to the reciprocating masses and use of four cranks spaced at intervals of 90, is so determined that the combined longi- 4-5", 90, 135. Inasmuch as a single crank, tudinal forces (i. e. the horizontal forces in connecting rod, piston and cross head unit the case of a horizontal engine) neutralize 80 cannot be balanced in both planes by any each other. I have discovered that this reweight placed on the crank-shafts, and since sult can be secured by counterweights so l0- with a crank spacing such as is specified the cated, without materially increasi the uncranks and connected reciprocating parts do balanced transverse forces (vertical forces in not balance each other in pairs, as they would the case of a horizontal engine). '85 do if placed at 90 intervals, a difficult balanc- As indicating the degree of overbalancing ing problem is presented- This is accentucharacteristic of this invention, it may be ated by the unusual size of such engines, the mentioned that good results were secured heavy masses thus encountered, and the relawith a uniflow engine having tail rods by tively high rotative speeds used. using about 25% overbalancing. 90 As a result of a study of the requirements In the accompanying drawings a typical 40 of uch a ngine I hav d vi d a Crank engine embodying the invention is illustrated order and an arrangement of counterweights y i y p q y the p ating on the shaft bymeans of which the total and Tolatmg Paris belng ShOWll- I u 0 u l 1,1 longitudinal stresses, occasioned by rotatlng 52- 1 1 F 95 and reciprocating parts, are almost completeg- 2 IS a 81(16 l nly neutral1zed,w1tho.ut materially exaggerat- Fig. 3 is an end elevation.

ing the transverse stresses occasioned by the The crank shaft 6 is shown as constructed rotating parts. This result-1s accomplished in two sections connected by flanges 7. The

by the use of only two counterweights. A main bearing journals are shown at 8, the

remarkably smooth-running engine is secheek pieces of the crank throws at 9 and cured. crank pins at 10.

In the following discussion itwill be under- The connecting rods are shown at 11, crossstood that the connecting rod is considered heads at 12, piston rods at 13, pistons at'14 and tail rods at 15. The pistons are shown as of the elongated type used with terminal exhaust engines.

There are four cranks distinguished by the letters A, B, C and D. The angular spacing is as follows,-A and C, 90 C and B, 135, B and D, 90; D and A, 45. The cylinder arrangement is symmetrical relatively to the longitudinal center line of the engine when viewed in plan. It is important that the cranks A and D, which are the 45 cranks to be counterweighted should be symmetrically disposed relatively to the longitudinal center line of the engine, and it is preferred but not essential that they be the end cranks as shown.

Each of the cranks A and D is provided with counterweights 16 preferably formed as extensions of the cheek pieces 9. The centers of mass of such counterweights lie in the plane which bisects the angle between cranks A and D, and the mass of each counterweight is such that the combined horizontal forces neutralize each other. To secure this result crank A and crank D are, each, together with the mass of their respective rods 11, somewhat overbalanced by their respective counterweights 16.

The crank arrangement shown in the drawing is that believed to be best. Here crank A leads crank B, crank B leads crank C and crank C leads crank D by the uniform angle of 135. Thus crank A leads crank D by 45.

The invention is not limited to the specific embodiment illustrated. For example, the two cranks at 45 with each other are those to be counterweighted. It is desirable, but not strictly essential, that the counterweights be located as closely as possible to the cranks which they counterbalance. Moreover, al though as stated, it is preferred to make these two cranks the end cranks of the four, any

arrangement in which these two cranks are symmetrically located on opposite sides of the longitudinal center line of the engine, would fall within the broad scope of the invention.

What is claimed is,-

1. In an engine, the combination of a crank shaft having four cranks, which considered successively along the length. of the shaft, are spaced each 135 angularly from the next, whereby the two end cranks are at 45 with each other; piston and connecting rod units of substantially uniform mass, one connected with each crank; and a pair of counterweights of substantially identical mass with one another mounted on said crank shaft near the ends thereof, and approximately opposite the end cranks, the centers of mass of said counterweights lying in a plane which bisects the angle between the e-nd cranks.

2. In an engine, the combination of a crank shaft having four cranks, which considered successively along the length of the shaft,

are spaced each 135 angularly from the next, whereby the two end cranks are at 45 with each other; piston and connecting rod units of substantially uniform mass, one connected with each crank; and a pair of counterweights each formed as extensions of the two cheek pieces of the two end cranks arranged with their centers of mass in a plane passing through the axis of said shaft and bisecting the 45 crank interval, said connterweights overbalancing their respective cranks in such degree that the forces of the revolving and reciprocating" parts of the engine in a direction parallel with the piston paths are substantially neutralized.

3. In an engine, the combination of a four throw crank shaft, having cranks spaced at successive angular intervals of 90, 45, 90 and 135, one with another, the two cranks at. 45 from each other being symmetrically located on opposite sides of the longitudinal center line of the engine: reciprocating parts of uniform mass and including a piston and connecting rod, each connected with a corresponding crank; and a pair of counter weights of substantially identical mass with each other, mounted on said shaft approximatel opposite those cranks which are at 45 with each other, the centers of mass of said weights lying in a plane which substantially bisects said 45 angle.

4. In an engine. the combination of a four throw crank shaft having cranks spaced at successive angular intervals of 90, 45, 90 and 185 one with another, the two cranks at 45 from each other being at o posite ends of the shaft, reciprocating parts of uniform mass and including a piston and connecting rod, each connected with a corresponding crank; and a pair of counterweights of substantially identical mass with each other, mounted on said shaft approximately opposite those cranks which are at 45 with each other, the centers of mass of said weights lying in a plane which substantially bisects said 45 angle. i

5. In an engine. the combination ofa four throw crank shaft having cranks spacedat successive angular intervals of 90, 45. 90 and 135 one with another, the two cranks at 45 from each" other" being symmetrically located on opposite sides of the longitudinal center line of the engine; reciprocating parts of uniform mass and including a piston and connecting rod each connected with a corresponding crank; and a pan of counter 'in such degree that the forces 'ofthe revolve ing and reciprocating partsof the engine in weights of substant-iallv identical mass with;

a direction parallel with the piston paths are substantially neutralized.

6. In an engine, the combination of a four throw crank shaft having cranks spaced at successive angular intervals of 90, 45, 90 and 135 one with another, the two cranks at 4:5 from each other being at opposite ends of the shaft; reciprocating parts of uniform mass and including a piston and connecting rod, each connected with a corresponding crank; and a pair of counterweights of substantially identical mass with each other, mounted on said shaft approximately opposite those cranks which are at 45 with each other, the centers of mass of said weights lying in a plane which substantially bisects said 45 angle, said comiterweights overbalancing their respective cranks in such degree that the forces of the revolxn'ng and reciprocating parts of the engine in a direction parallel with the piston paths are substantially neutralized.

In testimony whereof I have signed my namefco this specification.

RUDOLPH WINTZER. 

